It came as a dream: You’re dead, knocking at heaven’s gate.

The door is a handsome, heavy, cathedralish thing, and it won’t open. With calm worthy of a saint, you first rap nonchalantly. No answer.

As doubt and then frustration set in, you pummel and pound and even kick —- an intense, emotional barrage —- anything to make yourself heard on the other side.

Gradually, the desperate workout starts to make sense: The door is a musical instrument. When it finally opens, the reward sounds like a recap of your life, in all its exuberance and fear and corrupted innocence. By the end, knocking on heaven’s door seems like a purification ritual.

Karlheinz Stockhausen had this dream and —- as avant-garde philosopher-king of the 20th century, as the darling of Germany’s culture ministry, as a guru to pop stars from the Beatles to Bjork —- made it reality, or at least into an actual piece of music.

“Heaven’s Gate” was written for percussionist Stuart Gerber, a vital force on Atlanta’s new-music scene, a local performer with a global perspective. He’ll play the Atlanta premiere Saturday in a free concert devoted to the master’s music at Emory’s Performing Arts Studio.

At 35, Gerber, a hefty fellow, sports neatly trimmed beatnik facial hair and looks more like a student than a professor at Georgia State University, where he’s taught since 2001.

A decade ago he started studying with Stockhausen in Germany and wrote his doctoral dissertation on his percussion music. Nervously, he sent it to the composer.

“I was on MARTA coming home from my parents’ at Christmas,” Gerber recalls, “and I heard Stockhausen on my cellphone, I’ll never forget: He thanked me and said, ‘Every percussionist should read it.’

“I played that message again and again for my friends.”

Soon the composer invited the young American to teach his music to other percussionists at his annual symposium in Kurten, Germany, and found an inspiration for his dream.

Stockhausen commissioned a cabinet-maker to build the door with 12 wooden panels, each a different type of exotic wood yielding a different tone.

With two mallets in hand and heavy-soled shoes, Gerber gave the world premiere in Italy in summer 2006 and recorded it for the composer’s deluxe private label.

John Kennedy, who runs the contemporary music series at Charleston’s Spoleto Festival USA, booked Gerber to play the American premiere a year later.

“The work is a kind of performance art and the door becomes a passage, a catharsis, an existential relationship,” Kennedy offers. “The physical exertion and choreography make the idea powerful, but on a purely musical level, the sounds have a strong degree of interest. What makes it so gripping is the totality of the performance.”

After a performance of “Heaven’s Gate,” Gerber says he feels like he’s been in a boxing ring. “It pumps up the adrenaline and then I’m completely exhausted,” he says, “and I think the audience goes through that, too. The door might seem a little gimmicky on the surface, but Stockhausen was a perfect craftsman, and it’s a really good piece.

“It’s weird but it really works.”

A musical pioneer

Those words of unique praise —- unusual but great —- might be applied to Stockhausen throughout his life. From a family of farmers, he was orphaned during World War II as his patriotic Nazi father was killed in battle and his unstable mother was euthanized in a mental hospital.

After the war, he gravitated to atonal, ultra-modern music —- an art that severed the aural links to the romanticism embraced by most of European culture. He clearly needed to escape.

Perhaps to that end, he was always a pioneer.

First it was electronic music in the 1950s and later for happenings that were equal parts mysticism, science and deep humanity. Paul McCartney and John Lennon picked up that groove in the late 1960s: the Beatles’ “Sgt. Pepper’s” album is shot through with spooky or psychedelic sounds, and Stockhausen’s face is among the mass-media icons on the cover.

More recently, Icelandic pop vixen Bjork credits the Svengali for inspiration.

In his later years, says Spoleto’s Kennedy, “he was extending the Germanic tradition of music as a kind of spiritual quest. He was a 20th century Wagner, with his epic projects, a real mad genius.”

About the time the composer started to advance the fact that he was born on the star Sirius, American observers started to dismiss Stockhausen as indulgent and pretentious —- just as Europeans once dismissed the Minimalist movement, which largely supplanted his influence among young composers, as intellectually flimsy.

Yet Stockhausen still commanded celestially compelling events.

The “Helicopter String Quartet,” from 1994, requires four musicians, with microphones, playing in four different helicopters hovering over the concert venue. Inside, the audience listens over loudspeakers to the blend of violins and rotor blades whirring. It’s been performed several times and is captured on DVD.

“Heaven’s Gate” is also a part of a cosmic event, a 24-part series called “KLANG,” one for each hour of the day. (When someone asked, “Why is it loud and metallic at the end of ‘Heaven’s Gate?’ ” Stockhausen replied, “I wanted to show that heaven is not just ice cream.”)

He didn’t live to finish the cycle.

“With Stockhausen, he was so idealistic —- and had the funds to never compromise —- that he’d take his idea all the way to completion,” Gerber says.

At the time of Stockhausen’s death at age 79 in December 2007, Gerber called him “the most charismatic man imaginable.”

“When I arrived in the open graveyard area,” Gerber recalls about the funeral in Germany, “they were playing his music on CDs, and just as I walked toward the coffin ‘Heaven’s Gate’ came on. I knew it was a coincidence, but I couldn’t help but take it very personally; it was just an overwhelmingly spiritual experience.”

IF YOU GO

Music by Karlheinz Stockhausen. 8 p.m. Saturday. Free. Emory’s Performing Arts Studio, 1804 North Decatur Road. 404-727-5050, arts.emory.edu.